| M2K | Mew2King 
| Others |
| M2K | Miles to Kilometers
| Others |
| M2K | Music-to-Knowledge (A tool set for MIR/MDL development and evaluation)
| Others |
| M2L | Mobile to Land
| Others |
| M2L | Multi Media Laboratory
| Others |
| M2M | Machine to Machine
| Others |
| M2M | Many to Many
| Others |
| M2M | Missions to Military, Incorporated
| Others |
| M2M | Mobile to Mobile
| Others |
| M2M | Modified Delay Modulation Mark
| Others |
| M2M | Multipoint-To-Multipoint
| Others |
| M2O | Made to Order
| Others |
| M2O | Many to One
| Others |
| M2O | Market to Order
| Others |
| M2O | Nitrogen oxide
| Others |
| M2P | Merchant to Person
| Others |
| M2PA | Mtp2 Peer to Peer Adaptation Layer
| Others |
| M2S | Modified Delay Modulation Space
| Others |
| M2S | Multi-Mission Seeker
| Others |
| M2T | Maserati Biturbo
| Others |
| M2TS | MPEG-2 Transport Stream
| Others |
| M2U | Me To You
| Others |
| M2U | Music to You
| Others |
| M2UA | Mtp2 User Adaptation Layer
| Others |
| M2UNITY | Mazda 2 User Community
| Others |
| M2V | Machine to Vehicle
| Others |
| M2V | Mesh to Vehicle
| Others |
| M2V | Microgrid to Vehicle
| Others |
| M2V | Mobile to Vehicle
| Others |
| M2V | Motorcycle to Vehicle
| Others |
| M2V | MPEG-2 IPB videostream Video
| Others |
| M2W | Manufacturing 2 Wholesalers
| Others |
| M3 | Metalsmith 3rd Class Petty Officer
| Others |
| M3 | Modula3 language source code file
| Others |
| m3 | third marriage
| Others |
| m3/H | Cubic Meters per Hour
| Others |
| M3A | Sound (MPEG-3 audio)
| Others |
| M3AAWG | Messaging Malware and Mobile Anti Abuse Working Group
| Others |
| M3C | Bmw M3 Competition
| Others |
| M3C | Michiana Mini Motor Club
| Others |
| M3CS | Motorsport Three Series Club Sport
| Others |
| M3D | 3d animation macro (Corel Motion)
| Others |
| M3D | Magic Three Dimensional
| Others |
| M3E2 | Bmw M3 Evolution Two
| Others |
| M3G | Mobile 3D Graphics
| Others |
| M3LR | Tesla Model 3 Long Range
| Others |
| M3M | Millennium 3 Management Inc.
| Others |
| M3N | Mustang 360 Network
| Others |
| M3OC | Bmw M3 Owners Club
| Others |
| M3OC | Mazda 3 Owners Club
| Others |